The project would put state on track to have 40% of its power generated from wind.

DES MOINES — A utility company will invest $1.9 billion in wind energy in Iowa, the largest single economic investment in the state, officials announced.

When the MidAmerican Energy Co. project is complete, the utility that serves 714,000 customers in Illinois, Iowa, Nebraska and South Dakota expects its Iowa customers will receive 40% of their electricity from wind. Wind now generates about a quarter of Iowa’s electricity, the highest percentage nationwide.

“That is marvelous news,” Harold Prior, executive director of the Iowa Wind Energy Association, said Wednesday. “MidAmerican is one of the top utilities in the country as far as embracing wind energy.”

The state is considered the seventh windiest in the country, and the state already produces enough wind energy to power 1.1 million homes.

The project is expected to add 1,050 megawatts of wind generation, pushing the utility’s total to 3,335 megawatts of energy. It should create 460 construction jobs over two years and 48 permanent jobs, primarily workers needed to maintain the 656 wind turbines the utility will build through 2015, company officials said.

William Fehrman, MidAmerican Energy’s chief executive, said the project will hold down power costs for consumers.

“The reality is that you’re avoiding any kind of increase,” he said. MidAmerican Energy is a subsidiary of MidAmerican Energy Holdings Co., which Berkshire Hathaway (BRK.A) controls.

The company expects no net cost to its customers for the construction. The added wind generation is expected to cut consumer rates by $3.3 million in 2015 and $10 million annually by 2017, the company said.

“This is real money back in the pockets of Iowans,” Iowa Lt. Gov. Kim Reynolds said.

Iowa Gov. Terry Branstad and Fehrman said green energy has been critical to attracting companies like Facebook, the social networking giant that last month announced it will build a $300 million data center in Altoona, Iowa. State leaders expect Facebook to push its investment to nearly $1 billion over six years.

Facebook has pledged to get 25% of its energy from renewable resources by 2015. Ferhman said renewable energy was critical during negotiations with the California company. Facebook even explored the possibility of owning its own wind farm, state leaders have said.

“This sends a larger message to the nation that Iowa is cutting edge, Iowa is innovative,” Reynolds said.

Iowa ranks third in the USA, behind Texas and California, in its ability to generate electricity from wind, according to the American Wind Energy Association. Illinois and Oregon round out the top five. Iowa also is home to blade and turbine manufacturers whose components are used in generating wind energy.

MidAmerican Energy’s new, permanent jobs will create $2.4 million annually in pay for workers, the company said. Construction workers will take home $30 million, Reynolds said.

Other companies also have announced record-breaking investments in the past year in Iowa.

Orascom Construction Industries (ORSD.F) said it would build a $1.4 billion fertilizer plant in eastern Iowa, and CF Industries (CF) said it would invest $1.7 billion in its fertilizer plant near Sioux City, Iowa. Then Orascom recently said it would boost its investment to $1.8 billion.

Unlike those projects, MidAmerican Energy will receive no state incentives but will receive federal wind production tax credits.

“Without that, the environment for doing projects of this magnitude and this size would not be possible,” he said during a news conference at the state Capitol.

MidAmerican Energy already has erected 1,267 wind turbines, many in western and north-central Iowa. The company declined to say where the new wind farms would be located.

“If you look at a good wind map, you’ll probably get a good feel about where we’ll be targeting,” Fehrman said, adding that location decisions will be made in a couple of months.

The company’s new investment pushes MidAmerican Energy’s investment in wind to about $6 billion. The company said it already is No. 1 nationally in ownership of wind generation capacity among rate-regulated utilities.

Nathaniel Baer, who follows energy issues for the nonprofit Iowa Environmental Council, said MidAmerican’s announcement is encouraging, but he sees room for far more wind energy in Iowa than the utility is proposing. He hopes MidAmerican will make it easier for Iowans to install their own wind turbines in the utility’s territory by paying more for the power.

“I think it is a welcome development for wind energy, the Iowa environment and the economy,” Baer said of MidAmerican’s wind-energy expansion plans.

The U.S. Department of Energy has estimated that Iowa would have to boost its production significantly to help the nation meet environmental groups’ goal to have the country produce 20% of its power from wind by 2030.

In 1983, Iowa passed one of the country’s earliest renewable-energy laws, requiring its major utilities to own or contract a specific amount of renewable energy. MidAmerican Energy began building wind projects in 2004.

• Design is key. Bird mortality typically is relatively minor on Iowa-style wind farms, which differ sharply from the ocean-side, grid-style installments in California. In Iowa, turbines usually are installed along a ridge line, not in a grid, which makes birds less likely to collide with them. In California, strong ocean winds sometimes funnel birds through the tight formations of turbines.

• Windows are more dangerous. Multiple studies have found that many more birds die flying into windows or power lines than fly into wind-turbine towers, according to the Iowa Department of Natural Resources. Bat deaths are more common for unknown reasons.